So I was thinking about this game today and I realized something about detective mode.
When Batman enters a room full of thugs, he can tell how many enemies are there and how many have guns because they're all talking loudly, in plain view, making footsteps, clicking their guns, etc. You can hear all these noises as a player, but you don't piece together what they mean. Occasionally he doesn't see enemies who are hiding in vents or whatever because he has no reason to think they're there - particularly lunatics, because they operate on a wave pattern that Batman can't decipher with his logical mind.
I've always treated detective mode as, like, a filter that shows Batman all the information he needs in a room. I don't think I conceptually realized that it was actually viewing Batman's thought processes.
This game is bloody brilliant.